The random number generator is what the computer inside the poker machine uses to pick the symbol from each of the reels. It works like a lotto draw. It is as if the RNG puts a numbered ball for each position on the reel into a bucket and then shakes the balls up and picks one at random.

The ball that comes out is the position whose symbol will be displayed on that reel.

For example if the computer was to pick the position for reel shown above, it would put 32 balls number from 1 to 32 into a bucket and then pick one at random. If the ball was number
4 , the
symbol would be displayed. This is then repeated for each of the reels of the game.